1. Field of the Invention
The present invention relates to the measurement of and/or dispensing of minute quantities of liquids. More specifically this invention is directed to a transfer device for measurement and dispensing of fluids and particularly to a non-metallic transfer device for precision measurement and dispensing of less than 1 milliliter of a liquid. Accordingly, the general objects of the invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
Virtually all hypodermic needles presently manufactured have some metallic components within their structure. Thus, metal can be in some or all of the pistons, ferrules, needles and other syringe components. Metal is used in these circumstances for its strength. These metallic components can in some circumstances react with the fluid being dispensed, resulting in contamination of the measured fluid. For example, when titrating an acid, the acid can corrode the metal components of the syringe, resulting in contamination of the acid and possible failure of the syringe to properly operate. Friction within the syringe can also result in metal components wearing and contaminating fluids with metal particles. While these contamination problems could be avoided through the use of glass or a similar non-reactive material for all the components of a syringe, it has been widely known and accepted that the fragility of glass precluded its use as, for example, a small diameter piston. Accordingly, in the prior art, it has been exceedingly difficult to successfully measure and transfer small quantities of liquid without risk of metal contamination.